LIM DOMAINS - MULTIPLE ROLES AS ADAPTERS AND FUNCTIONAL MODIFIERS IN PROTEIN INTERACTIONS

The LIM domain is a specialized double-zinc finger motif found in a va riety of proteins, in association with domains of divergent functions or forming proteins composed primarily of LIM domains. LIM domains int eract specifically with other LIM domains and with many different prot ein domains. LIM domains are thought to function as protein interactio n modules, mediating specific contacts between members of functional c omplexes and modulating the activity of some of the constituent protei ns. Nucleic acid binding by LIM domains, while suggested by structural considerations, remains an unproven possibility. LIM-domain proteins can be nuclear, cytoplasmic, or can shuttle between compartments. Seve ral important LIM proteins are associated with the cytoskeleton, havin g a role in adhesion-plaque and actin-microfilament organization. Amon g nuclear LIM proteins, the LIM homeodomain proteins form a major subf amily with important functions in cell lineage determination and patte rn formation during animal development.